The Justice Department ramped up pressure Wednesday on so-called sanctuary cities seeking public safety grant money, warning that they could be legally forced to prove they are cooperating with federal immigration authorities.

The move prompted immediate backlash, with mayors from across the country announcing they would boycott a planned meeting at the White House with President Donald Trump on Wednesday afternoon. Denver's mayor, Michael Hancock was among them.

"This is a destructive ploy by the Trump Administration’s lawyers to politicize a routine exchange of information. We will repeat what we have said time and again, Denver does not violate section 1373 and complies with all federal laws," he said in a statement.

Denver has tried to walk a fine line between protecting its undocumented residents from Immigration and Customs Enforcement -- ICE -- while Hancock also asserts the city is not a sanctuary city.

"Denver won’t back down. We are joined by dozens of other communities, resolute in opposing chaotic and poorly reasoned overreach by Attorney General Sessions and we will not stand down from doing what is right. There are hundreds of Mayors in DC who have been invited by Trump to the White House today. I refuse to meet with the President under these kinds of threats and fear mongering," Hancock said.

Federal officials sent letters to roughly two dozen jurisdictions threatening to issue subpoenas if they don't willingly relinquish documents showing they aren't withholding information about the citizenship or immigration status of people in custody. The department has repeatedly threatened to deny millions of dollars in important grant money to communities that refuse to comply with a federal statute requiring information-sharing with federal authorities, as part of the Trump administration's promised crackdown on cities and states that refuse to help enforce U.S. immigration laws.

Many cities have been openly defiant in the face of the threats, with lawsuits pending in Chicago, Philadelphia and California over whether the administration has overstepped its authority by seeking to withhold grant money.

The move angered members of the U.S. Conference of Mayors who had been set to meet with Trump on Wednesday to discuss infrastructure, drug addiction and other topics.
New Orleans Mayor Mitch Landrieu, the conference president, said in a statement that "the Trump administration's decision to threaten mayors and demonize immigrants yet again — and use cities as political props in the process — has made this meeting untenable."

"The U.S. Conference of Mayors is proud to be a bipartisan organization. But an attack on mayors who lead welcoming cities is an attack on everyone in our conference," he said.
New York's Bill de Blasio announced his boycott on Twitter.

"I will NOT be attending today's meeting at the White House after @realDonaldTrump's Department of Justice decided to renew their racist assault on our immigrant communities," he wrote, adding that the move "doesn't make us safer and it violates America's core values."

Trump spokeswoman Sarah Huckabee Sanders said the White house has been very clear that it doesn't support sanctuary cities and supports enforcing and following the law. "If mayors have a problem with that, they should talk to the Congress, the people that pass the laws. The Department of Justice enforces them, and as long as that is the law, the Department of Justice is going to strongly enforce it."

As for the mayors, she said the White House would love to work with them, "but we cannot allow people to pick and choose what laws they want to follow."

"If we have a country with no laws, then nothing matters," Sanders added.

The 23 jurisdictions that received letters Wednesday also include cities in Illinois, New York, California, New Mexico, Washington, Mississippi, Massachusetts, Kentucky, Vermont and Oregon. Officials said the places were previously warned that they need to provide information about their policies to be eligible to receive grants that pay for everything from bulletproof vests to officer overtime.

Attorney General Jeff Sessions has blamed "sanctuary city" policies for crime and gang violence, saying Wednesday, "we have seen too many examples of the threat to public safety represented by jurisdictions that actively thwart the federal government's immigration enforcement_enough is enough."

But defenders of sanctuary city practices say they actually improve public safety by promoting trust among law enforcement and immigrant communities and reserving scarce police resources for other, more urgent crime-fighting needs.